\begin{tikzpicture}
    \tkzDefPoints{0/0/M, 4/0/N, 1/1.5/A,  2.5/1.0/B}
    \tkzDrawSegments(M,N)
    \tkzDrawPoints(A,B)
    \tkzLabelPoints[below](M,N)
    \tkzLabelPoints[left](A)
    \tkzLabelPoints[right](B)
\end{tikzpicture}

